Well, close range weapons work well on Epitaph and Snowbound simply because of the shield doors. That’s why shotguns and maulers are vital weapons to control on each map.
The only way to force an open field strategy on Snowbound is if you control the shotgun, sniper, possibly laser and some mid-long range weapons like the carbines or battle rifles. Duck into the bases when you’re weak, easily taking them down with a shotgun or mauler if they chase.
Epitaph is simply run and gun, catching people off guard and forcing them into positions they don’t want to be. Rockets are handy, but are generally good for only 4 kills, assuming you don’t waste one in a shield door. Again, shotguns, maulers, and even plasma rifles come in handy on this map. You don’t even have to camp, but use the doors to your advantage.
However, for Snowbound, the most common strategy is to camp the shotgun spawn. Be careful of the canisters that line the walls around the shotgun. Grenades can cause those things to explode through the shield door, and ultimately kill anyone close. But, have someone camp the doors to each base, and someone with some range watch the larger shield door. Last person might be ducking in and out of the hole in the middle to draw them in, or enticing people through the other doors.